Motor, refrigeration machine or heat pump

ABSTRACT

When not only integrating the compressor and expander, but also the heat exchanger in one single rotor, a machine working according to the gas turbine process can be simplified. The gas turbine process in such a machine can also be run in reversed mode as a refrigeration machine or heat pump. Lower relative velocities between the working fluid and the components of the machine can be used which should lead to lower frictional losses and a higher efficiency. In order to further reduce the friction the rotor should rotate in a chamber with low pressure or in a medium with lower friction than air. The medium that exchanges heat with the working medium here called the heat carrying fluid is also taken into the rotor.

BACKGROUND OF THE INVENTION

A machine according to this invention works as a motor according to thegas turbine cycle (the Joule/Brayton cycle) or as a refrigerationmachine or heat pump according to the reversed gas turbine cycle. Theinvention thus includes a machine that can run either as a motor whenthe produced shaft power is utilised, a refrigeration machine when theproduced cooling power is used or as a heat pump when the heating poweris utilised. In both the motor case and the refrigeration/heat pump casea working medium is being compressed, heat is being added or subtracted,and the working medium is thereafter expanded. If heat is being added tothe compressed working medium in the heat exchanger, the machineaccording to the invention will become a motor. If heat on the otherhand is subtracted, the machine according to the invention will become arefrigeration machine or a heat pump. The main components, thecompressor, the heat exchanger and the expander are according to theinvention joined into one single rotating part, hereinafter called therotor. Two media are flowing through the rotor, namely, the workingmedium that is compressible and the heat carrying fluid. When themachine is used as a motor, hot oil could be used as a heat carryingfluid and for instance air as working medium. Alternatively anexothermal reaction for instance combustion in the working medium itselfcan be used as a heat carrying fluid. When the machine is used as arefrigeration machine/heat pump air can be used as a working medium andfor instance water as heat carrying fluid.

In another form of the machine, when the working medium is notatmospheric air, an additional heat exchanger is needed to another fluidcalled the cold carrying fluid. In the motor case, the cold carryingfluid is absorbing heat while in the refrigeration or heat pump case, itis delivering heat to the working medium.

In a third form of the machine as a motor, the mechanical energy outputis delivered fully or partly from an external expander. If the machinein this form is run as a heat pump or refrigeration machine, the rotorrotation and the propulsion of the working medium are accomplished fullyor partly with an external compressor.

The gas turbine cycle is normally accomplished by first compressing theworking medium (normally air) in a separate compressor after which it isheated in a separate combustion chamber and finally is expanded in aseparate turbine. In all three components the velocity relative to thewalls, guidevanes and blades are high which results in frictionallosses.

Heat pumps similar to the invention are shown in the Swedish patents122418 and 163924. According to the first patent, the heat carryingfluid is led outside the rotating heat exchanger whereby the velocitydifference between the heat carrying fluid and the heat exchangersurface becomes large and the frictional losses between the heatcarrying fluid and the heat exchanging surface becomes large. In thesecond patent an attempt to reduce the velocity difference between therotating heat exchanger and the heat carrying fluid has been made, byintroducing a secondary separating wall, so that the velocity differenceis divided into two parts. This method will not likely result in anespecially large reduction of the frictional losses.

A similar idea is also described in GB 1443802A. In this invention theheat exchange is integrated with the compressor, and the expander isplaced on a separate shaft so that the expander is not rotating with thesame angular velocity as the compressor. FR2699653A1 describes anothersimilar idea where the compression among other things is accomplishedwith an axial compressor. In DE2729134-A, a machine is described whereamong other things the heat is transferred by radiation from the heatcarrying fluid which runs outside the machine and where the coldcarrying fluid runs centrally in the machine. The patent GB2128310 showsan advanced magnetic construction where the heat carrying fluid runs inthe surround stator body and the cold carrying fluid runs through theshaft. In U.S. Pat. Nos. 2,490,064 and 2,451,873 solutions are shownwhere the heat exchange takes place during the compression phase and notas in our invention at substantially constant pressure. The U.S. Pat.No. 2,490,064 and GB-1420722 differ from our invention as the heatcarrying fluid is not rotating inside the rotor.

OBJECT OF THE INVENTION

One goal with the suggested machine is to minimise the losses duringcompression, heat exchange and expansion by reducing the relativevelocity of the working medium to the different parts of the machinecompared to the normal process with a separate compressor, heatexchanger and expander. That should lead to lower losses and anincreased efficiency. Another goal is to let both the working medium andthe heat carrying fluid run through channels in the rotor. The relativevelocity between the two media can then be regulated to a value requiredby the heat exchange and no more. In order to reduce the frictionallosses of the rotor it must rotate surrounded by low pressure or aspecial medium resulting in low friction.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following text the invention is described with reference to thefollowing figures in which:

FIG. 1 schematically shows the path of the working medium and the heatcarrying fluid through the rotor,

FIG. 2 shows an example of the path of the working medium and the heatcarrying fluid through a real rotor,

FIG. 3 schematically shows the path of the working medium using anexternal compressor in an open loop and

FIG. 4 shows use of an external compressor in a closed loop.

DETAILED DESCRIPTION

In FIG. 1 it is shown how the working medium (WM) with centers at point1, is compressed as the compressor blades 2 forces the medium to rotatewhereby the centrifugal force increases the pressure and temperature.Thereafter the working medium absorbs or delivers heat in the heatexchanger 3. Finally the working medium is expanded in the passagethrough the expander blades 4 whereby pressure and temperature falls.The working medium leaves the machine through the outlet 5. The heatcarrying fluid (HF) enters the machine at point 6, is pumped radiallywith the pump 7 after which the heat carrying fluid delivers or absorbsheat in the heat exchanger 3. Finally the heat carrying fluid passes theturbine 8 and out through he exit 9. The rotational axis is onlyindicated with a line in FIG. 1.

In FIG. 2 the way of the paths of the working medium (WM) and the heatcarrying fluid (HF) are shown through a real rotor. The blades of thecompressor 2 and of the expander 4 are shown more in detail here. Thepath of the working fluid through the compressor and expander is limitedby through the rotors outer end plates 18 and inner end plates 19. Inthis example, the heat exchanger 3 is formed as a chamber limited by aninner rotor cylinder 12 and an outer rotor cylinder 14 in which a spiralshaped pipe with outer flanges 13 is placed. The heat carrying fluidenters through the shaft 10 via the inlet 6, is then brought to the heatexchanger through the indicated pump channel 7, runs through the flangedheat exchanger pipe 13 to finally exit through the turbine channel 8 andout through the heat carrying fluid outlet 9 in the shaft 10. It couldalso be anticipated that the heat exchanger is an integral part of theinner rotor cylinder 12. The outer surface of the inner rotor cylinder12, is then wholly or partly joined with the shaft 10 utilising radiallyheat conducting material whereby the heat carrying fluid is led throughthe shaft and heat is radially conducted.

As shown in FIG. 1, the entrance radius R1 of the working medium (WM) at1 can be made smaller than the exit radium R5 at 5. A driving force forthe flow of the working medium is then automatically achieved. The inletradius R6 of the heat carrying fluid (HF) 6 can be made smaller than theexit radius R9 in the heat carrier exit at 9. A driving force for theflow of the heat carrying fluid is then automatically achieved. Therotor rotates in a stator chamber 15, that is limited by an outer statorcylinder 16 two stator end plates 11 and two seals 17 to the rotor. Thestator chamber 15 is preferably connected to a vacuum pump or filledwith a medium resulting in low frictional losses.

In FIG. 3 it is shown how an external compressor 20, in an open processcan set the rotor into rotation whereby the radius for the working fluidin the inlet 1 can be made just as large as the radius in the outlet 5.

FIG. 4 shows in the refrigeration machine/heat pump case how the workingmedium is driven into the rotor inlet 1 by an external compressor 20.From the rotor outlet 5 the working medium is then led to a heatexchanger 22 which in the refrigeration/heat pump case is heated by acold carrying fluid. The heat carrying fluid enters through the shaft at6 and exits at 9 in this case.

What is claimed is:
 1. A rotary machine that can be used as at least oneof a motor, a refrigeration machine, and a heat pump, said rotarymachine comprising: a rotor through which both a working medium and aheat carrying fluid are directed during mutual heat exchange, said rotorcomprising a compressor, a heat exchanger and an expander; means fordirecting the working medium through the heat exchanger in a firstdirection; and means for directing the heat carrying fluid through theheat exchanger in a second direction opposite to said first direction;wherein the working medium is first directed radially outwards throughthe compressor, then axially through the heat exchanger, and finallyradially inwards through the expander; and wherein the mutual heatexchange between the working medium and the heat carrying fluid issubstantially carried out under constant pressure in the heat exchanger,where the working medium and the heat carrying fluid are directed incounter current flow.
 2. The rotary machine according to claim 1,wherein said means for directing the working medium through the heatexchanger in the first direction at least partly comprises forming anouter radius at an inlet to the compressor to be smaller than an outerradius at an outlet of the expander, so that a pressure is induced whichcauses the working medium to flow through the heat exchanger in thefirst direction.
 3. The rotary machine according to claim 2, whereinsaid means for directing the heat exchanger fluid through the heatexchanger in the second direction at least partly comprises forming anouter radius at an inlet for the heat carrying fluid to be smaller thanan outer radius at an outlet for the heat carrying fluid, so that apressure is induced which causes the heat carrying fluid to flow throughthe heat exchanger in the second direction.
 4. The rotary machineaccording to claim 1, wherein said means for directing the heat carryingfluid through the heat exchanger in the second direction at least partlycomprises forming an outer radius at an inlet for the heat carryingfluid to be smaller than an outer radius at an outlet for the heatcarrying fluid, so that a pressure is induced which causes the heatcarrying fluid to flow through the heat exchanger in the seconddirection.
 5. The rotary machine according to any one of claims 1-4,wherein: the rotor includes a rotor cylinder; and the rotary machinefurther comprises a stator chamber arranged outside the rotor cylinder,said stator chamber being at least one of put under low pressure andfilled with a medium giving lower frictional losses than air.
 6. Therotary machine according to any one of claims 1-4, wherein said meansfor directing the working medium through the heat exchanger in the firstdirection at least partly comprises an external compressor.
 7. Therotary machine according to any one of claims 1-4, wherein the workingmedium flows through the rotary machine in a closed loop.
 8. The rotarymachine according to any one of claims 1-4, further comprising anexternal heat exchanger, and wherein the working medium exchanges heatwith a cold carrying fluid in the external heat exchanger.